Solve for $t$ : $-17 + t = 15$
Add $17$ to both sides: $ \begin{eqnarray} \\ -17 + t &=& 15 \\ \\ {+17} && {+17} \end{eqnarray} $ $ \begin{eqnarray} \hphantom{-17 + t} &\hphantom{=}& \hphantom{15} \\ t &=& 15 {+ 17} \\ \end{eqnarray} $ Simplify. $ t = 32$